A Taste of Mocha

@eschoff - @funkytek - @wearefractal

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contact@wearefractal.com

Open source is at github.com/wearefractal

Terminology

TDD

Test Driven Development

Write tests before any code is written
Traditionall uses X-Unit

"Make sure the code works"

ATDD

Acceptance Test Driven Development

Should be readable by the business guys
Team driven

"Make sure the features are correct"

BDD

Behaviour Driven Development

Extends TDD
Uses ATDD
Team driven

"Should, given, when, then"

Test. Relax.

Wouldn't it be nice to be confident about what you have in production?

Wouldn't it be nice to guarantee your code works and have the tests to prove it?

Tested code is good code.

Give yourself peace of mind and just test.

Mocha

simple, flexible, fun

Features

Browser support
Async support
Code coverage tools
Extensible DSLs
Interfaces to suit your style (BDD by default)
Hooks for pre and post processing
Diffs for reporting

Diffs

Simplicity

Your test is a simple function that takes a callback.

You do your checks and balances within the function.

You call the callback when you are done.

function test(done){
  assert.equal(1, 1);
  done();
}

Simple right?

You can also pass errors to done() to make things easier

BDD Interface

var assert = require("assert");
describe('Array', function(){
  describe('#indexOf()', function(){
    it('should return -1 when the value is not present', function(done){
      assert.equal(-1, [1,2,3].indexOf(5));
      assert.equal(-1, [1,2,3].indexOf(0));
      done();
    });
  });
});

Categorize your tests with 'describe'
These can be nested as deep as you want
Describe a specific test with 'it'

TDD Interface

var assert = require("assert");
suite('Array', function(){
  suite('#indexOf()', function(){
    test('should return -1 when not present', function(done){
      assert.equal(-1, [1,2,3].indexOf(5));
      assert.equal(-1, [1,2,3].indexOf(0));
      done();
    });
  });
});

Categorize your tests with 'suite'
These can be nested as deep as you want
Describe a specific test with 'test'

Exports Interface

var assert = require("assert");

module.exports = {
  'Array': {
    '#indexOf()': {
      'should return -1 when not present': function(done){
        assert.equal(-1, [1,2,3].indexOf(5));
        assert.equal(-1, [1,2,3].indexOf(0));
        done();
      }
    }
  }
};

Categorize your tests by wrapping it in an object
These can be nested as deep as you want
Describe a specific test or category with object key

Reporters

Spec Reporter

Dot Matrix Reporter

Nyan Cat Reporter

Hooks

before and after = one test

beforeEach and afterEach = every test

You can nest these as deep as you want.

The names change between interfaces but are all the same.

Hooks (BDD)

describe('Connection', function(){
  var db = new Connection();
  var tobi = new User('tobi');
  
  // wipe the databse
  beforeEach(db.clear);
  
  // seed the database with fake data
  beforeEach(function(done){
    db.save(tobi, done);
  });

  describe('#find()', function(){
    it('should respond with matching records', function(done){
      db.find({ type: 'User' }, function(err, res){
        if (err) return done(err);
        assert.equal(res.length, 1);
        done();
      });
    });
  });
});

Let's Test

Installation

npm install -g mochagit clone https://github.com/wearefractal/mocha-adventurecd mocha-adventure

Add/Substract

cd test/add
mocha .
cd test/subtract
mocha .

Add the missing code to match the test

Mult/Divide

cd test/multiply
mocha .
cd test/divide
mocha .

Add the missing test to match the code

Calc - Finish

mocha .

Add the missing test for all functions